1. Water, sanitation, hygiene & environmental health Pete Kolsky Energy and Water Department

2. Outline Some facts about water, san and health Historical evolution Classification by transmission The Literature of impact studies The nature of the problem Conclusions for practitioners

3. Some water, sanitation and health numbers Faecal-oral (focus of this presentation) Diarrhoeal disease 2 million deaths/year from diarrhoea, mostly under 5 Jumbo jet crash every hour and a half … One billion cases/year 4.3% of Burden of Disease DALYs 88% (?) attributable to inadequate WSH 1/3 of developing world pop ’ n carry intestinal worms 200 million infected by schistosomiasis (bilharzia) 6-9 million blind from trachoma (1/4 reduced by adequate water supply)

4. Natural chemical hazards Arsenic Skin lesions, various cancers “ 20 to 60 ” million exposed in Bangladesh Major problem other parts of S. Asia, also Argentina, Chile, China, Hungary, Mexico, Peru Fluorosis Dental damage, crippling bone damage “ affects millions ” (WHO) but often of mild form

5. Historical evolution: water quality and health John Snow Cholera Broad Street Pump 1854 Water Companies' Studies William Budd Typhoid in 1850's-60's Koch Cholera vs.Pettenkoffer Hamburg/Altona 1892 1937 Croydon Typhoid And many more…

6. Characteristics of these (and other) waterborne outbreaks 1.True outbreaks … sudden spikes Very visible and dramatic!! Politically hot! 2.Common source … the water supply If you ’ re a water engineer … you don ’ t want one on your watch! Cholera is the water engineer ’ s best friend … Money for chlorine suddenly becomes available … 3.Until 1970s, water quality dominated environmental health perception of diarrhoea

7. Classifications of disease Classification usually by organism (viral, bacterial, etc) or organ (diseases of head, heart, liver etc.) Classification by transmission route Bradley ’ s great innovation in 1970s If you know how it ’ s spread, you know how to stop it … … so engineers loved it!

8. The F-Diagramme Faeces Future Victim Fluids Fingers Flies Fields/ Floors Sanitation Food HygieneWater supply

9. The great debates of the 80s Water-borne or water-washed? Is water quality or water quantity more important? Review of epi in ‘ 83 revealed fundamental challenges Blum, D. and R. Feachem, Int J Epidemiol 1983, 12, pp. 357-365 Lack of control One-to-one (clustreing) Confounding variables (inc. age) Recall Diarrhoeal definition Usage Seasonality These issues are real, and are still grave threats to ‘quick and dirty’ project level impact assessments!!

10. Results from Esrey, 1985 Type of Intervention No of Results Median Reduction All interventions5322 Water quality916 Water availability1725 Water quality and availability 837 Excreta disposal1022 (Esrey, S.A. et al., WHO Bull, 63(4): 757-772, 1985) Range 0-100 0-90 0-100 0-82 0-48

11. Esrey (1985) by disease Disease or infection No of results Median reduction Cholera1141 Shigella2748 Entamoeba histolytica 172 Giardia lamblia 100 Range 0-91 0-81 0-80 0-20

12. Esrey ’ s update in 1991 Esrey et al., WHO Bull, 69(5): 609-621 (1991) Intervention NoMed % reduct NoMed % reduct Water & San 720230 Sanitation 1122536 Water Quality and Quantity 2216217 Water Quality 717415 Water Quantity 727520 Hygiene 6336 All Studies Rigorous Studies

13. 2004 Fewtrell, Colford update Why do more? More studies Statistically rigorous meta-analysis HH water treatment new player “Water, sanitation and Hygiene: Interventions and diarrhoea A systematic review and meta-analysis”, Lorna Fewtrell and John M. Colford, Jr. HNP Discussion Paper, World Bank 2004. Water, sanitation, and hygiene interventions to reduce diarrhoea in less developed countries: a systematic review and meta-analysis, L. Fewtrell, R. Kaufmann, et al. Lancet Infectious Diseases, Vol 5, pp 42-52. Jan 2005.

14. Some of the main results Above are highlights … Strong, detailed report and bibliography, and documentation of approach

15. Previous reviews: a – dEsrey SA et al. (1991) Bull WHO 69 (5): 609-621 eCurtis V, Cairncross S (2003) Lancet Inf Dis 3: 275-281. Taken from S. Cairncross RWSSTG BBL “ The Health Impact of Sanitation ”, Aug 2004.

16. Major new conclusions from Fewtrell, Colford, Kaufmann Water quality at HH is shown as significant … further reviews forthcoming … some skeptics remain Hygiene is reconfirmed as an effective intervention Combining interventions does not appear to have synergistic effect, contrary to popular public health belief

17. A step back from all of this … We don ’ t live in an “ average ” world … Mountains of Peru are different from slums of South Asia e.g. soil and food contamination risks higher in China, Vietnam than in Africa … Briscoe (Briscoe, J., Am J Epidemiol 1984;120:449-55) sheds even more light in a non-linear world… If disease incidence not linearly proportional to transmission, then “impact” attribution easily skewed

18. The F-diagramme revisited Faeces Future Victim Fluids Fingers Flies Fields/ Floors Sanitation Food HygieneWater supply

19. Ward City River & Environs Peri- domestic (street, school, work- place) Home How people see their city

20. (street,school, workplace) Peri- domestic Street Sewers Home House Connections An environmental view Central Treatment Works City Collectors Ward

21. A public health view

22. Take home messages … Diarrhoea is a huge problem in child health Water, sanitation and hygiene can reduce diarrhoea between 25-50% … Very broad consensus that: Focus on the household … Hygiene matters! Water quality matters, but it ’ s not “ just ” water quality … faecal contamination gets around many ways Sanitation, WS infrastructure can make hygiene possible! Health studies are tough … live with indicators rather than “ health outcome ” HH water treatment continues to be a growing focus of attention … perhaps even more relevant for chem. contam.

23. Thank you for your attention!